SPECTRA OF SOME OF THE BRIGHTER STARS. 
709 
The next star in the series is Bellatrix, the line at X 4471 increasing in intensity, 
while the line at X 4481 has almost disappeared. 
In the next stage, represented by ^ Orionis, an important new line at X 4088 makes 
its appearance, but all the chief lines of Bellatrix are retained. 
a Virginis is the next star in the series, and here again it is clear that the con¬ 
tinuity is unbroken, the hydrogen lines also being broader than in the stars already 
dealt with. 
yd Persei and a Andromedse are the representatives of the sub-divisions which come 
next in the sequence, and in these also it will be seen that there is perfect continuity. 
From a Herculis to a Andromedse, we thus have a continuous series of spectra, the 
dark flirtings first disappearing, and afterwards most of the lines of the more common 
metals such as iron and manganese, lines of unknown origin gradually replacing them. 
At the same time, the amount of continuous absorption is gradually diminishing, and 
the lines of hydrogen are increasing in intensity. 
We now come to the second series (Plate 29), and here it is quite an easy matter 
to begin where the first series left off, namely, with such a star as a Andromedge. In 
these stars, as already pointed out, there are no certain indications of iron. There 
are other stars, however, such as Sirius and a Geminorum in which there are all the 
important lines of a Andromedse, and, in addition, some of the lines of iron. 
In the stars which come next in the sequence, represented by ^ Arietis, there is an 
intensification of the metallic lines, and a slight diminution in the breadth of the 
hydrogen lines. This goes on through the various sub-divisions represented by 
a Persei, a Canis Minoris, a Aurigse, and a Bootis, the hydrogen lines thinning out 
as the metallic lines thicken. Continuous absorption in the ultra-violet commences in 
the later stars of the series. 
Thus, from a Andromedee to Arcturus there is a perfectly continuous series of 
spectra.. 
IX.—DISCUSSION OF RESULTS IN RELATION TO THE METEORITIO HYPOTHESIS. 
(1.) Phenomena to be Expected on the Hypothesis. 
Reference io Classification based on Eye Observations. 
We are now in a position to consider the various divisions of the photographic 
spectra already arrived at, in relation to the groups which were previously suggested 
from a discussion of eye observations. This classification was as follows :— 
Group I.—Badiation lines and flutings predominant. Absorption beginning in the 
last species. 
Group II.—Mixed radiation and absorption predominant. 
* ‘ Roy. Soc. Proc.,’ vol. 44, p. 26. 
